Resinous reaction products derived from lignins



United States Patent 3,121,709 REMNOUS REACTEQN PRODUCTS DERIVED FROM HGNINS Lothar Engelmann, Sudhury, Mass, assignor to Chemtan Company, Exeter, NE, a partnership of New Hampshire No Drawing. Filed Aug. 22, 196i), Ser. No. 50,355 15 (Ilaims. (Cl. 260-124) This invention relates to the preparation of novel chemical compounds, and particularly to novel resinous reaction products prepared from certain lignin materials. The compounds referred to can be described in general as the reaction products of an alkali lignin with a resinforming amino compound, a salt of an aromatic sulfonic acid and formaldehyde.

The alkali lignins are believed to be of value for certain industrial purposes because of the presence in their molecules of free hydroxyl groups and also because of the substantial absence of sulfo groups. However, they have been found to have the disadvantage of being insoluble in water under even slightly acid conditions. As part of the experimentation leading to the present invention, attempts were made to render the alkali lignin soluble in the presence of acid by reacting it with aromatic sulfonic acids. To accomplish this the alkali lignin was refluxed in aqueous alkaline solution with aromatic sulfonic acids, such as the sodium salt of sulf-anilic acid. However, continued refluxing did not prevent precipitation occurring immediately upon the addition of diluted acetic acid to the diluted reaction mixture. was made to interact alkali lignin with formaldehyde, and it was likewise found that immediate precipitation occurred under the same conditions. In fact this reaction resulted in the formation of a product of much higher viscosity, which showed even less solubility in water than the alkali lignin alone.

According to the present invention it is possible to obtain Water-soluble reaction products which are substantially acid stable upon dilution with water by interacting in aqueous alkaline solution an alkali lignin with a resin-forming amino compound of the type selected from the group consisting of melamine, guanylurea, guanidine, urea and dicyandiamide; a salt of an aromatic sulfonic acid and formaldehyde in certain specified proportions, and heating the mixture together under reflux. If the reaction is carried out by reacting a predetermined amount of alkali lignin with one mol of the amino compound, and at least one mol of the sulfonic acid salt and two mols of formaldehyde, water-soluble products are obtained which after dilution with water do not immediately precipitate upon the addition of acid, such as acetic acid or formic acid. However, by increasing the amount or ratio of formaldehyde, products are obtained which precipitate more readily in the presence of acid. For example, in the case of products obtained by reacting a given amount of alkali lignin with one mol of the amino compound, two mols of formaldehyde and one mol of the sulfonic acid salt, the addition of formic acid did not produce a precipitate immediately; whereas the products prepared in the same way but with the use of 3 mols of formaldehyde precipitated slightly, and products prepared with 4 mols of formaldehyde produced a distinct precipi tatae under the same condition.

While the mechanism of the above reaction is not completely understood, it is believed that under conditions of reflux the various additives condense or couple together, largely due to the presence of the formaldehyde as a condensing or coupling agent, and as a result compounds are formed in which the alkali lignin, amino compound, formaldehyde and the aromatic sulfonic acid A similar attempt substituent groups.

as Indulin is manufactured under conditions that insure salt are reacted and combined. The products obtained were stable solutions which, after dilution, precipitated only at relatively low pH values upon the addition of acid.

The alkali lignins employed are derived from the manu facture of paper pulp by the sulfate process. A typical alkali lignin material suitable for the purposes of this invention is prepared in a variety of forms by the Polychemicals Division of the West Virginia Pulp and Paper Company and sold under the trademark Indulin. Certain of these products are insoluble in Water, but are soluble in aqueous alkali. Others are prepared in the form of sodium derivatives, which are soluble in water since they form an alkaline solution without adding alkali. Thus, the various forms of Indulin differ from each other primarily in alkalinity, and can be used interchangeably in their alkaline form or in alkaline solution. lln general, the alkali lignins are naturally occurring polymers, characterized by a series of closely linked benzene, pyrane and furane rings carrying methoxyl, hydroxyl and other The particular alkali lignin known a uniform product completely free of Wood sugars and similar wood degradation products, and has the following characteristics Y Methoxy groups percent 13.9 Hydroxy groups do 14.5 Calculated molecular Weight based on 4 methoxy groups 840 Number of methoxy groups per 840 unit 4 i Number of hydroxy groups 8 Ash percent 0.5-23 Moisture do 3-9 While a wide variety of salts of aromatic sulfonic acids can be used to make the reaction products of this invention, I preferably employ an alkali salt of a naphthol sulfonic acid or of an amino sulfonic acid of the benzene or naphthalene series. Suitable compounds for this purpose include, for example, the sodium, potassium and ammonium salts of sulfanilic acid, naphthionic acid, 0- naphthionic acid, S-amino-l-naphthalene sulfonic acid, l-naphthol-4-sulfonic acid, and 2-naphthol-6-sulfonic acid.

Suitable amino compounds for the purposes of this invention include melamine, guanylurea, guanidine, urea, and dicyandiamide, and other similar resin-forming amino compounds. The formaldehyde employed in the reaction can be used in various forms also. However, it is preferable to employ the aldehyde in the form of paraformaldehyde.

The reactions are in general carried out by charging the materials into a three necked flask equipped with stirrer, reflux condenser and thermometer, heating the materials to reflux and refluxing for about 2 hours or more. Similar reactions have been described in a copending application, but in which the resin-forming amino compound was omitted. By using such amino compounds along With the alkali lignin, the sulfonic acid salt and formaldehyde in accordance with the present invention, it is believed that products of increased molecular size and different properties are formed, in which the formaldehyde serves to condense and unite both the alkali lignin and the resin-former, and the resin-former and the salt of the aromatic sulfonic acid.

The effect of reacting the several ingredients in various proportions can be readily ascertained from the following table, in which the results of several tests are tabulated. The materials were in each instance charged into a three necked flask equipped with stirrer, reflux condenser and thermometer, heated to reflux and refluxed for 3 hours. In each case the sodium salt of alkali lignin was reacted with dicyandiamide, sodium sulfanilate and paraformaldehyde. The particular sodium salt of alkali lignin used in these tests was a product sold by the West Virginia Pulp and Paper Company under the trademark Indulin C, which has the characteristics hereinbefore stated and also an average impurities content of 25%. Inasmuch as the molecular weight of the alkali lignins, including lndulin C, is a matter of conjecture, the products represented by this table were of necessity obtained by reacting a predetermined amount in grams of the sodium salt of alkali lignin with molar quantities of the other reactants. Since the paraformaldehyde was 91% pure, one mol would be contained in 33 grams of the aldehyde. The molecular weight of sodium sulfanilate containing 21-1 is 231.2.

TABLE I Test Number 1 2 3 Water grains, 1 200 200 200 Sodium Salt of alkali lignin. d 80 80 80 pHCHO. 11.3 16.9 22.5 pHCHO M0 at Sodium s 43.1 43.1 43. 1 0 i 0 V0 it a Dreyandiam1de. 15. 7 15. 7 15. 7 o *lio 7in fiis Reflux time 3 3 3 Ratio of grams of lignin to mols of dieyandiarnide to mols of pHCI-IO and mols ofsulfanilate X:1:2:1 X:1:31 X:1:4:1 Consistency Precipitation pI-I 1. 95 2. 3 3. G

1 X equals 426 grams of the sodium salt of alkali lignin.

2 Viscous liquid.

3 100 milliliters of a 5% solution of each reaction product in water was titrated with 4 N formic acid until the solution clouded. The results were accurate within the range of or 0.2 pH.

In the tests shown in Table I the materials were all charged into the reaction flask together. In the tests shown in the following table, on the other hand, the materials were charged separately, or in stages, and in varying order, and then were refluxed for one hour after each charge. In each instance also the proportion of the reactants used was the same.

ucts which are less soluble in the presence of acid than those containing only two molar proportions of the aldehyde. Likewise the degree of solubility of the products in water in the presence of acid varies in accordance with the procedure used in charging the reactor. Thus, the precipitation pH varied from about 3.6 to less than 1.9, depending on the method employed.

In a further test similar to test number 8, it was found that if the sodium sulfanilate and the sodium salt of alkali lignin were first reacted with one mol of paraformaldehyde for one hour prior to being added to the reaction product of one mol of dicyandiamide and four mols of paraformaldehyde, the end product is more acid sensitive than any of the other products tested. Thus, the products prepared in this way with an end molar ratio of 1 mol of sodium sulfanilate to 1 mol of dicyandiamide to 5 mols of paraforrnaldehyde to 426 grams of the sodium salt of alkali lignin precipitated in the pH range of 3.4 to 3.8 as compared with 1.9 (or lower) to less than 3.0 for most of the other products.

A further understanding of the invention will be obtained from the following examples of methods of preparing water soluble reaction products suitable for the 5 purposes of this invention.

Example I 200 milliliters of water, 80 grams of alkali lignin (Indulin C), 43 grams of sodium sulfanilate crystals, 15.7 grams of melamine and 11.3 grams of paraformaldehyde were charged to a 3 necked flask equipped with a stirrer, reflux condenser and thermometer. The mixture was brought to reflux and reflux for 3 hours. After cooling to room temperature this solution had a pH value of about 9, was of syrupy consistency, free of formalin odor and dilutible with water in any ratio. It remained stable for at least 9 months, and when diluted did not precipitate until sufficient formic acid was added to bring the solution to a pH of 1.9.

TABLE 11 Test Number 4 5 A0-.. n 1. H2O lignin pHCI-IO.

1. Hi0 lignin pI-ICHO.

3 c. 1. Dicyandiamide pHGHO A6 1. H20 pHCHO sulfanilate.

"Me" 1. 1110 pHOHO sulfanilate.

Charge procedure )o)lut1on H1 2 2. Sulianilate 2. Dicyandiamide 2. Lignin 2. Dicyandiamide... 2. sulfanilate. 3. Dieyandiamide 3. sulfanilate 3. Di0yand1am1de..- 3. Lig-nin 3. H 0 li nin, Reflux time 1 hour after each 1 hour after each 1 110111 after each 1 hour after each 1 hour after each charge; 3 hours Charge; 3 hours charge; 3 hours charge; 3 hours charge; 3 hour t tal, total. total. total. Ratio of grams of lignin to mols of X:1:4;1 X:l:4:1 X1 1 1 Xzlzzl X:l:4:1.

dieyandiamide to mols oi pHCHO and mols of sulfanilate. 4 Consistency Viscous liquid Viscous liquid V1scous liquid Viscous liquid VlSCOUS liquid. Precipitation pH 2.5 2. 1.9. 1. 3.4.

The value of X In the ratios of Table II is the same as Example II defined at the bottom of Table I. Likewise, the precipitation pH values in Table II were determined in the manner described at the bottom of Table I.

The results as shown in Tables I and 11 indicate that products which are substantially stable in the presence of acid can be obtained by reacting 426 grams of the alkali lignin with one mol of dicyandiamide and at least two mols of paraformaldehyde and one mol of sodium sulfanilate. Thus, when proportions such as these are used, the reaction products do not precipitate in the presence of acids, such as ace-tic acid or formic acid, until the solution has a pH value of about 3.6 or lower. It is also to be noted that an increase in the relative amount 250 milliters of water, 80 grams of alkali lignin (In dulin C), 15 grams of urea and 15 grams of parafornialdehyde were charged to a 3 necked flask equipped with a stirrer, reflux condenser and thermometer. The mixture was brought to reflux and refluxed for 1 hour. 43.5 grams of sodium sulfanilate crystals and 5.7 grams of additional paraformaldehyde were then added, and the mixture was refluxed for another 2 hours, after which the solution was cooled. The reaction product was of syrupy consistency, had a pH value of 8.6 and was free of formalin odor. It remained stable for at least 1 month and was capable of being diluted with water in any ratio. A diluted solution of the reaction product did not precipitate until sufficient of paraformaldehyde used in the reaction results in prodformic acid was added to bring the solution to a pH of 2.3.

Example 111 200 milliliters of water, 80 grams of alkali lignin (Indulin C), 11.3 grams of paraformaldehyde, 43.5 grams of sodium sulfanilate crystals, 15.8 grams of dicyandiamide The leathers treated as described above were full, somewhat firm, and had a medium smooth grain, a tight break, and showed good plumping. Cloth and paper treated with these products had increased body or feel,

were Charged to a reaction flask, refluxed and further 5 incretased strength and the decreased tendency to absorb mots ure. 223:1: sg t gzig fi ggf g z ig ggggfi izg ggg While the water soluble reaction products which do not also possessed other properties of the product described in prec'lpltate m the Presenc? of acld's will the P Value 15 Example L lowered to at least 6, or m some instances as low as 1.9, Example IV 10 or even lower, are particularly useful 1n the previously mentioned industrial fields, the neutral or alkaline water mlnlhters of Water grams of alkah hgmn soluble reaction products of this invention, which precipi- 43 r s of sodwm sulfamlate crystals, tate immediately in the presence of acids, are also useful grams of dicyandlamlde grams of parflfofmalde as impregnation agents, and can be used to advantage in hyde were charged to a reactlon flask refluxed and further 15 the treatment of fabrics, paper and other similar materials. treated as in Example I. The resulting solution displayed What I claim the same properties as the product of Example I eXCePt 1. The water-soluble reaction product obtained by inthat a Prficipitate Was formed p the addltion of formic teracting in an alkaline water solution an alkali lignin acid of a pH of 3.6. with an amino compound selected from the group conple V sisting of melamine, guanylurea, guanidine, urea and di- 200 milliliters of water, 80 grams of the sodium salt cyandiamide? EQ Y Substfificfi sfilected f lk li h i d h C), 433 grams of sodium from the group consisting of alkali salts of naphthol sulnaphthiohate, 15 7 grams f melamine and 113 grams of fornc acids and alkali salts of amino sulfonic acids of paraformaldfihyde Wem Charged to a 3 necked flask the benzene and naphthalene senes, and heating the aqueequipped as in Example I, and refluxed for 3 hours, after 25 macho mlxture under l v which the solution was cooled to room temperature and Z i w f m mactlon q t g d bomech The resulting sglution had the same properties teracting rn an alkaline water solution alkali lignm with as the reaction Product described in Example L melamine, rormal dehyde and a substance selected from the group consisting of alkali salts of naphthol sulfonic Example V1 acids and alkali salts of amino sulfonic acids of the 250 milliliters of water, 7.5 grams of NaOH, 73.8 grams benziflm and nailhthalene Series, and heating the aqueous of raw 1-naphthol-4-sulfonic acid (58.8%), 80 grams of reaction miXfl-lffi under uX. alkali lignin (Indulin C), 15.7 grams of melamine and tfhewater-soluifle Teactlofl Product Obtal'md y 113 grams f r fo ld h d were charged to a 3 teractmg in an alkaline water solution alkali lignin with necked fl k squippsd as in Example 1, and fl d f g uanylurea, formaldehyde and a substance selected from 3 hours, Cooled to room temperature and 1 The tne group consisting of alkalrsalts of naphthol sulfonic resulting solution had the same properties as the reaction acids and alkali Salts of ai mn0 lf n acids of the product d i d i Example 11 benzene and naphthalene series, and heating the aqueous The alkali lignin used in the above examples is known reacilon mixture under i the trade as Induhn C, hi is prepared in the f 40 4. The water-soluble reaction product obtained by inf the sodium salt and is th f soluble in Water teracting in an alkaline Water solution alkali lignin with soluble forms f alkali .h such as the pure f f guanldme, formaldehyde and a substance selected from alkali hgnih known as Induhn may also be used, if the group CGIlSlS't'lIlg of alkali salts of naphthol sulfonic a small amount f alkali is added to the reaction mixture acids and alkali salts of amino sulfonic acids of the ben- The resinous reaction products prepared as described naphthaline Series and heating the q eous ft:- above are useful in the treatment of penetrable materials, won mlxtuu under reflllx- I such as tanned leather, fabrics and paper. For example, T water'solutfle reactlon P 'Q Obtained by mshaved chmmstanned leather was first Washed for 10 teracting in an alkallne Water solution alkali lignin with minutes at F and drained It was then floated i1 urea, formaldehyde and a substance selected from the 100% Water at F. after which 5% (based on the group consisting of alkali salts of naphthol sulfonic acids solids content) of one of the products referred to in table and alah E of iflmmo sulfopslc acids of the benzene I diluted in 25% Water at F was addfid and the and naphthalene series, and heating the aqueous reaction leather was drummed for minutes, and drained. It was mlxmm under then washed 5 minutes at 130 F., drained, and then T f reaction P Q P y {11- fioated in Watsr at R A conventional fat 50 te racting in an alkaline water solution alkali ltgnm with liquor in 25% Water at F. was then added, after dicyandtarntde, formaldehyde and a substance selected Which the treated leather was drummed 45 minutes, or group cfimsisfillg of a ali Salts of naphthol suluntil the fatliquor was exhausted, horsed up and air dried. 01110 flclds and alkali l s f amino sulfonic acids of When samples of chrome-tanned leather were treated 60 the bfinzene l naphthalene Sales, and heatlllg the q with the products of tests 1, 2 and 3 (Table I), the follow- 0118 reaction mixture under reflux. i results were d 7. The Water-soluble reaction product obtained by in TABLE III Fatli uor Leather Produ et t g l l lg Product q pilcggrllrtg Temper Grain Break test No test 1W- siil ianilate pH Exhaustion pH Exhaustion .2 Fair 9.0 M s-M T. .2 Fairto Good" 11.5 M-F S-M T. .4 do 9.0 M-F S-M '1. Fatliquor Complete 0 S-M M T.

control.

Symbols:

Temper: S-Solt; M-Mellow; F-Firm. Grain: S-Qrnooth; M-Medium; D-Drawn. Break: T-Tight; M-Medium; L-L0ose.

teracting in an alkaline Water solution alkali lignin with an amino compound selected from the group consisting of melamine, guanylurea, guanidine, urea and dicyandiamide; formaldehyde, and the sodium salt of suifanilic acid, and heating the aqueous reaction mixture under reflux.

8. The Water-soluble reaction product obtained by interacting in an alkaline Water solution alkali lignin with an amino compound selected from the group consisting of melamine, guanylurea, guanidine, urea and dicyandiamide; formaldehyde, and the sodium salt naphthionic acid, and heating the aqueous reaction mixture under reflux.

9. The Water-soluble reaction product obtained by interacting in an alkaline Water solution alkali lignin with an amino compound selected from the group consisting of melamine, guanylurea, guanidine, urea and dicyandiamide; formaldehyde, and the sodium salt of S-amino-lnaphthalene sulfonic acid, and heating the aqueous reaction mixture under reflux.

10. The water-soluble reaction product obtained by in teracting in an alkaline Water solution alkali lignin with an amino compound selected from the group consisting of melamine, guanylurea, guanidine, urea and dicyandiamide; formaldehyde, and the sodium salt of l-naphthol- 4-sulfonic acid, and heating the aqueous reaction mixture under reflux.

11. The Water-soluble reaction product obtained by interacting in an alkaline Water solution alkali lignin with an amino compound selected from the group consisting of melamine, guanylurea, guanidine, urea and dicyandiamide; formaldehyde, and the soduim salt of 2-naphthol 6-sulfonic acid, and heating the aqueous reaction mixture under reflux.

12. The Water-soluble reaction product obtained by interacting in an alkaline water solution alkali lignin With dicyandiamide, paraformaldehyde and the sodium salt of sulfanilic acid, and heating the aqueous reaction mixture under reflux.

13. The Water-soluble reaction product obtained by interacting in an alkaline Water solution 426 grams of an alkali lignin with one mol of an amino compound selected from the group consisting of melamine, guanylurea, guanidine, urea and dicyandiamide; at least two mols of a polymer of formaldehyde and one mol of a substance selected from the group consisting of alkali salts of naphthol sulfonic acids and alkali salts of amino sulfonic acids of the benzene and naphthalene series, and heating the aqueous reaction mixture under reflux.

14. The method of preparing Water-soluble reaction products which comprises interacting in an alkaline Water solution an alkali lignin with an amino compound selected from the group consisting of melamine, guanylurea, guanidine, urea and dicyandiamide; formaldehyde, and a substance selected from the group consisting of al kali salts of naphthol sulfonic acids and alkali salts of amino sulfonic acids of the benzene and naphthalene series in the roportion of 426 grams of the alkali lignin With one mol of the amino compound, and at least two mols of formaldehyde and one mol of said substance, and heating the aqueous reaction mixture under reflux until the reaction product remains clear on diluting it with Water and acidifying.

15. The method of preparing Water-soluble reaction products which comprises interacting in an alkaline water solution an alkali lignin with an amino compound selected from the group consisting of melamine, guanylurea, guanidine, urea and dicyandiamide; formaldehyde, and a substance selected from the group consisting of alkali salts of naphthol sulfonic acids and alkali salts of amino sulfonic acids of the benzene and naphthalene series in the proportion of 426 grams of the alkali lignin With one mol of the amino compound, and at least tWo mols of formaldehyde and one mol of said substance, and heating the aqueous reaction mixture until the reaction product remains clear on diluting it with Water and acidifying.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 121 709 February 1-8, 1964 Lothar Engelmann It is hereby certified that error'appears in the'above numbered patent requiring correction and that the said Letters Patentshould read as corrected below Column 3, TABLE I column 3, line 4 thereof for "9/10" read 9/16 same table, same column, line 6 thereof -f0r "3/10" read 3/16 column 5, line 19 for "of" read to Signed and sealed this 11th day of August 1964.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents ERNEST w. SWIDER' Attcs'tirig Officer 

1. THE WATER-SOLUBLE REACTION PRODUCT OBTAINED BY INTERACTING IN AN ALKALINE WATER SOLUTION AN ALKALI LIGNIN WITH AN AMINO COMPOUND SELECTED FROM THE GROUP CONSISTING OF MELAMINE, GUANYLUREA, GUANIDINE, UREA AND DICYANDIAMIDE; FORMALDEHYDE, AND A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF ALKALI SALTS OF NAPHTOL SULFONIC ACIDS AND ALKALI SALTS OF AMINO SULFONIC ACIDS OF THE BENZENE AND NAPTHALENE SERIES, AND HEATING THE AQUEOUS REACTION MIXTURE UNDER REFLUX. 